Project Summary/Abstract Improved understanding of the brain processes underlying normal and abnormal function is necessary for devising better ways to diagnose, alleviate, or cure neurological or psychiatric disorders. It is clear that even for simple behaviors, such processes depend on interactions among multiple brain regions. However, these interactions themselves are less well understood. This inadequate understanding of inter-regional interactions impedes the generation of substantive models of brain functions and the new diagnostic or therapeutic possibilities that such models could introduce. These de?ciencies re?ect in part the limitations of the widely used imaging modalities. Detailed analysis of the operation of a network of brain regions requires comprehensive coverage, high spatial resolution, and high temporal resolution. However, existing techniques either lack high temporal resolution, high spatial resolution, or comprehensive coverage. Thus, they cannot track the spatial and temporal progression of inter-regional interactions. Intracranial recordings using electrocorticographic (ECoG) electrodes placed on the brain surface, or depth electrodes (stereoencephalography; SEEG) placed in regions and sulcal depths not accessible with ECoG, can provide wide coverage and high temporal and spatial resolution. Furthermore, electrical stimulation through these electrodes can assess causal roles and inter-regional connections. However, because intracranial electrodes are only available in patients awaiting brain surgery, intracranial studies are typically limited to small numbers of subjects with variable electrode coverage. In the research proposed here, our established and highly experienced ECoG/SEEG consortium will engage in a formalized research program that seeks to begin to reveal the detailed connectivity, causality, and dynamic neural processes supporting human speech perception. Research to achieve our two project aims will take full advantage of the opportunities afforded by intracranial electrodes. The proposed work will make use of an established interdisciplinary intracranial consortium, with four data collection sites providing access to dozens of subjects per year. The consortium will apply itself to answering new questions about dynamic inter-areal function underlying speech perception. If successful, the proposed work should not only add new neuroscienti?c understanding, but also formally validate a consortium structure as a model for intracranial research.